Cooling/heating apparatus using waste heat from fuel cell

ABSTRACT

Disclosed herein is a cooling/heating apparatus using waste heat from a fuel cell. The cooling/heating apparatus comprises a fuel cell, a hydrogen modifying unit, a cooling/heating unit, and refrigerant heating units. The cooling/heating unit includes at least one compressor, a four-way valve, an outdoor heat exchanger, an expansion device, and an indoor heat exchanger, to establish a heat pump type refrigerant cycle. The refrigerant heating units provide waste heat recovered from the fuel cell and the hydrogen modifying unit to a suction-side refrigerant line connected to the suction side of the compressor included in the cooling/heating unit to raise the temperature of a refrigerant. During a heating operation, the cooling/heating apparatus can achieve an enhancement in heating performance and an enhancement in system efficiency.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to a cooling/heating apparatus using wasteheat generated from a fuel cell, and, more particularly, to acooling/heating apparatus in which waste heat generated from a fuel cellduring a heating operation is supplied to the suction side of acompressor to achieve an enhancement in heating efficiency.

2. Description of the Related Art

In general, fuel cells are electrochemical devices in which the chemicalenergy of fuel is converted directly into electrical energy via anelectrochemical reaction. Considering the basic principle thereof, thefuel cells are adapted to produce electricity by oxidation of hydrogenobtained by modifying fossil fuels, such as petroleum or natural gas, orpure hydrogen. During the oxidation of hydrogen, heat and water vaporare generated as byproducts.

The fuel cells can be generally classified, in accordance with the kindof currently available electrolytes, into four types includingphosphoric acid fuel cells (PAFC), molten carbonate fuel cells (MCFC),solid oxide fuel cells (SOFC), and proton exchange membrane fuel cells(PEMFC).

FIG. 1 is a schematic configuration diagram illustrating a conventionalcogeneration system using waste heat from a fuel cell.

As shown in FIG. 1, the conventional cogeneration system includes a fuelcell 10, and a water tank 20 which provides cooling water to absorb heatgenerated from the fuel cell 10. The cooling water of the water tank 20is adapted to circulate through the interior of the fuel cell 10,thereby serving to keep the interior temperature of the fuel cell 10 atan appropriate level and to recover waste heat from the fuel cell 10.

In succession, the heat, recovered from the fuel cell 10 using thecooling water, is accumulated in the water tank 20, and, finally, theresulting hot water is supplied to a domestic or building heatingsystem, such as a hot-water supply source or a hot-water boiler.

In FIG. 1, reference numeral 12 designates a generator cutoff switch,and reference numeral 14 designates an electrical wiring provided in anelectric appliance.

When it is desired to heat a confined space in winter, the conventionalcogeneration system using the fuel cell 10 as stated above is adapted toutilize electricity generated from the fuel cell 10 or a boiler usingthe waste heat from the fuel cell 10.

In the case of using the boiler, however, there is a problem in that thescale of the cogeneration system excessively increases and requiresadditional costs for the driving of the boiler. On the other hand, inthe case of using electricity, the cogeneration system suffers fromdegradation in overall system efficiency because the cogeneration systemcannot use the waste heat from the fuel cell 10.

SUMMARY OF THE INVENTION

Therefore, the present invention has been made in view of the aboveproblems, and it is an object of the present invention to provide acooling/heating apparatus in which waste heat generated from a fuel cellis supplied to a heating unit, which uses a refrigerant cycle, therebyachieving an enhancement in the recovery efficiency of the waste heat,and, consequently, an enhancement in heating performance.

In accordance with the present invention, the above and other objectscan be accomplished by the provision of a cooling/heating apparatususing waste heat of a fuel cell comprising: the fuel cell; acooling/heating unit which includes at least one compressor, a 4-wayvalve, an outdoor heat exchanger, an expansion device, and an indoorheat exchanger, to establish a heat pump type refrigerant cycle; and arefrigerant heating unit to provide the waste heat recovered from thefuel cell to a refrigerant line of the cooling/heating unit so as toraise the temperature of a refrigerant.

Preferably, the refrigerant heating unit may be configured to supply thewaste heat to a suction-side refrigerant line connected to the suctionside of the compressor.

Preferably, the refrigerant heating unit may include: a cooling waterline to transfer the heat recovered from the fuel cell; and a heataccumulation tank to transfer the heat, supplied via the cooling waterline, to the suction-side refrigerant line connected to the suction sideof the compressor.

Preferably, the cooling water line may be provided with a temperaturesensor and a flow rate sensor to measure the temperature and flow rateof cooling water, respectively, and is also provided with a coolingwater pump to circulate the cooling water and a flow-rate control valveto adjust the flow rate of the cooling water.

Preferably, the heat accumulation tank may be connected to a line whichreceives the heat transferred via the cooling water line and suppliesthe heat to a heat demand unit.

Preferably, the suction-side refrigerant line, connected to the suctionside of the compressor, may be provided with a bypass line and valves tocause the refrigerant to bypass the heat accumulation tank.

Preferably, the cooling/heating apparatus may further comprise: ahydrogen modifying unit to supply hydrogen to the fuel cell; and arefrigerant heating unit for the hydrogen modifying unit which supplieswaste heat recovered from the hydrogen modifying unit 150 to asuction-side refrigerant line connected to the suction side of thecompressor included in the cooling/heating unit.

Preferably, the refrigerant heating unit for the hydrogen modifying unitmay include: a cooling water line to transfer the heat recovered fromthe hydrogen modifying unit; and a heat accumulation tank to transferthe heat, supplied via the cooling water line, to the suction-siderefrigerant line connected to the suction side of the compressor.

Preferably, the cooling water line may be provided with a temperaturesensor and a flow rate sensor to measure the temperature and flow rateof cooling water, respectively, and is also provided with a coolingwater pump to circulate the cooling water and a flow-rate control valveto adjust the flow rate of the cooling water.

Preferably, the heat accumulation tank for the hydrogen modifying unitmay be connected to a line which receives the heat transferred via thecooling water line and supplies the heat to a heat demand unit.

Preferably, the suction-side refrigerant line, connected to the suctionside of the compressor, may be provided with a bypass line and a valveto cause the refrigerant to bypass the heat accumulation tank.

With the cooling/heating apparatus using the waste heat from a fuelcell, the waste heat generated from the fuel cell or hydrogen modifyingunit during a heating operation is able to be supplied to therefrigerant line of the cooling/heating unit. Thereby, it is possible toachieve an enhancement in heating performance and an enhancement inoverall system efficiency.

Further, since the cooling water can be supplied to the refrigerantline, in a state of being appropriately adjusted in the amount andtemperature thereof in accordance with a load variation of the fuel cellor hydrogen modifying unit, it is possible to supply uniform heat to therefrigerant line, enabling an implementation of the heating operation.

BRIEF DESCRIPTION OF THE DRAWINGS

The above and other objects, features and other advantages of thepresent invention will be more clearly understood from the followingdetailed description taken in conjunction with the accompanyingdrawings, in which:

FIG. 1 is a schematic configuration diagram illustrating a conventionalfuel cell system;

FIG. 2 is a schematic configuration diagram illustrating acooling/heating apparatus using waste heat from a fuel cell according toa first embodiment of the present invention; and

FIG. 3 is a schematic configuration diagram illustrating acooling/heating apparatus using waste heat from a fuel cell according toa second embodiment of the present invention.

DESCRIPTION OF THE PREFERRED EMBODIMENTS

Hereinafter, exemplary embodiments of a cooling/heating apparatus usingwaste heat from a fuel cell according to the present invention will beexplained with reference to the accompanying drawings.

Although a number of embodiments may be implemented for thecooling/heating apparatus using waste heat from a fuel cell according tothe present invention, the following description will be given inconjunction with the most preferable embodiment.

FIG. 2 is a schematic configuration diagram illustrating acooling/heating apparatus using waste heat from a fuel cell according toa first embodiment of the present invention.

As shown in FIG. 2, the cooling/heating apparatus according to the firstembodiment of the present invention comprises a fuel cell 50 taking theform of a stack of a plurality of cells. The fuel cell 50 is preferablyformed of a proton exchange membrane fuel cell (PEMFC), but the presentinvention is not limited thereto, and, admittedly, other various kindsof fuel cells may be used.

The fuel cell 50 is adapted to generate heat by inducing anelectrochemical reaction. In consideration of such a heat generationmanner of the fuel cell 50, the cooling/heating apparatus of the presentinvention further comprises a cooling unit 52, which serves to cool thefuel cell 50 to thereby adjust the interior temperature of the fuel cell50 to an appropriate level.

The cooling unit 52 includes a heat accumulation tank 53 in which heatexchange is performed, and a cooling water line 54 through which coolingwater flows to transfer heat, recovered from the fuel cell 50, to theheat accumulation tank 53.

The heat accumulation tank 53 may be configured to store cooling water,which flows through the cooling water line 54, or may be configured tostore a heat transfer fluid, which receives heat from the cooling waterwhen it passes the cooling water line 54. Admittedly, the heataccumulation tank 53 may be made of a heat conductive material, such asmetal, to heat exchange with the cooling water flowing through thecooling water line 54.

The cooling water line 54 has a pipe shape, and is configured to beinserted into the stack of the fuel cell 50, in the same manner as aconventional cooling water passage.

The cooling water line 54 is provided with a plurality of controllers tocontrol the temperature of the cooling water in consideration of thefact that the fuel cell 50 has an excessive temperature variation. Thecooling water line 54 is further provided with a cooling water pump 55to circulate the cooling water, a temperature sensor 56 to measure thetemperature of the cooling water, and a flow-rate sensor 57 to measurethe flow rate of the cooling water. In addition, the cooling water line54 is provided with a flow-rate control valve 58 to adjust the amount ofthe cooling water flowing through the cooling water line 54 inaccordance with results sensed by the temperature sensor 56 and theflow-rate sensor 57.

The heat accumulation tank 53 is connected to a heat supply line 59,which receives heat transferred via the cooling water line 54, andsupplies the heat to a certain heat demand place or heat demand unit.The heat-supply line 59 is provided with a valve 59V to open or close afluid path. Here, the heat demand place or heat demand unit isselectable from among a variety of systems that require a heat source,such as a hot-water supply device or heating system.

The cooling/heating apparatus according to the first embodiment of thepresent invention further comprises a cooling/heating unit 60, whichuses a heat pump type refrigerant cycle using waste heat generated fromthe fuel cell 50. The cooling/heating unit 60 includes at least onecompressor 61, a 4-way valve 62, an outdoor heat exchanger 63, anexpansion device 64, and an indoor heat exchanger 65 as in a generalheat pump type cooling/heating apparatus which can be used as a heatingunit in accordance with reversal of a refrigerant flow in a refrigerantcycle. For reference, reference numeral 66 designates an accumulator.

In particular, the cooling/heating apparatus further comprises arefrigerant heating unit adapted to supply the waste heat recovered fromthe fuel cell 50 to a refrigerant line of the cooling/heating unit 60 soas to raise the temperature of the refrigerant. In the presentembodiment, the cooling unit 52 of the fuel cell 50 serves as therefrigerant heating unit. In this case, the refrigerant line of thecooling/heating unit 60 extends through the heat accumulation tank 53,so that the waste heat of the fuel cell 50 is transferred to therefrigerant line.

Preferably, the refrigerant line, which is adapted to receive the wasteheat from the fuel cell 50, is a suction-side refrigerant line 67connected to the suction side of the compressor 61, or a discharge-siderefrigerant line connected to the discharge side of the compressor 61.In the illustrated embodiment of the present invention, the suction-siderefrigerant line 67 connected to the suction side of the compressor 61is adapted to receive the waste heat from the fuel cell 50.

The suction-side refrigerant line 67, connected to the suction side ofthe compressor 61, is provided with a bypass line 68 and valves 69,which allow the refrigerant to bypass the heat accumulation tank 53during a cooling operation or in the case of overheating of therefrigerant.

The cooling/heating apparatus of the present invention further comprisesa control unit 70 to automatically control the apparatus in accordancewith the inputted operation condition and operational state. The controlunit 70 is designed to receive signals from the temperature sensor 56and the flow-rate sensor 57, and to control the cooling water pump 55,the flow-rate control valve 58, the valve 59V of the heat supply line59, and the valves 69 of the cooling/heating unit 60, based on thesignals. Admittedly, the control unit 70 may be configured to controlthe general control operations of both the fuel cell 50 and thecooling/heating unit 60.

Operation of the cooling/heating apparatus using the waste heat of thefuel cell according to the first embodiment of the present invention,having the above-described configuration, will now be described.

The cooling/heating apparatus according to the first embodiment of thepresent invention is able to obtain all energy, required to drive boththe outdoor and indoor units during a heating operation in winter, fromelectricity and waste heat generated from the fuel cell 50. Here, as thewaste heat from the fuel cell 50 is heat exchanged with the suction-siderefrigerant line 67 connected to the suction side of the compressor 61,it is possible to achieve an enhancement in heating performance.

The electricity generated from the fuel cell 50 is used in elementsrequiring electricity, such as the compressor 61 or fan of thecooling/heating unit 60 and other various control equipment.

In the cooling/heating unit 60, a heating operation in winter is carriedout as the refrigerant is circulated through the compressor 61, 4-wayvalve 62, indoor heat exchanger 65, expansion device 64, and outdoorheat exchanger 63, in this order. In this case, the refrigerant to beintroduced into the compressor 61 via the suction-side refrigerant line67 is pre-heated by the heat of the cooling water used to cool the fuelcell 50 while passing through the heat accumulation tank 53. Thepre-heated refrigerant is then introduced into the compressor 61.

By pre-heating the refrigerant at the suction side of the compressor 61using the waste heat from the fuel cell 50, the refrigerant is adaptedto pass through the indoor heat exchanger 65 serving as a condenser, ina state of being maintained at a more or less increased temperature.Accordingly, heat of a higher temperature can be supplied to the room,so that it is possible to achieve an enhancement in heating performance.

In operation, the control unit 70 continuously controls the bypass line68, the valves 69, the flow-rate control valve 58, and the valve 59V ofthe heat supply line 59 to supply uniform heat to the suction-siderefrigerant line 67 connected to the suction side of the compressor 61.Thereby, it is possible to appropriately control the cooling operationof the fuel cell 50 and the operation of the cooling/heating unit 60.

As stated above, in the present invention, a proton exchange membranefuel cell (PEMFC) is used as the fuel cell 50. In this case, although anoperating temperature of the fuel cell 50 is 80 degrees, the interior ofthe fuel cell 50, in which a chemical reaction is practically induced,exhibits a temperature deviation of approximately 40 to 100 degrees.Also, the flow rate of the cooling water, which circulates in the fuelcell 50, must be changed to maintain the operating temperature of thefuel cell 50 at an appropriate level, in accordance with load of thefuel cell 50.

In the present invention, as the control unit 70 controls all of thevalves 58, 59V, and 69 based on a variation in the flow rate of thecooling water in accordance with load of the fuel cell 50 and interiortemperatures of the cooling water line 54 and the heat accumulation tank53 sensed via the temperature sensor 56 and the flow-rate sensor 57, itis possible to supply uniform heat to the refrigerant line of thecooling/heating unit 60.

FIG. 3 is a schematic configuration diagram illustrating acooling/heating apparatus using waste heat from a fuel cell according toa second embodiment of the present invention. For reference, constituentelements of the configuration shown in FIG. 3, identical to those of theconfiguration shown in FIG. 2, are designated by the same referencenumerals as those of FIG. 2, respectively, and no description thereofwill be given.

In general, fuel cells, such as solid oxide fuel cells (SOFC), moltencarbonate fuel cells (MCFC), and proton exchange membrane fuel cells(PEMFC), utilize a hydrogen modifying unit which obtains hydrogen fromfuel, such as methanol, liquefied natural gas, or natural gas. Thecooling/heating apparatus according to the second embodiment of thepresent invention is configured so that waste heat generated from thehydrogen modifying unit 150 as well as the fuel cell 50 is supplied to asuction-side refrigerant line 167 connected to the suction side of thecompressor 61, thereby achieving a further enhancement in heatingperformance.

Here, the hydrogen modifying unit 150 is connected to the fuel cell 50via a hydrogen supply line 151.

The hydrogen modifying unit 150 is also connected to a modifying unitcooling unit 152, which is used to absorb heat generated during ahydrogen modifying operation of the hydrogen modifying unit 150.

The modifying unit cooling unit 152 includes a heat accumulation tank153 in which heat exchange is performed, and a cooling water line 154through which cooling water flows to transfer heat, recovered from thehydrogen modifying unit 150, to the heat accumulation tank 153.

The heat accumulation tank 153 for the hydrogen modifying unit 150 mayhave the same configuration as that of the heat accumulation tank 53 forthe fuel cell. 50 as stated above.

In the same manner as that of the fuel cell 50, the cooling water line154 of the hydrogen modifying unit 150 is provided with a cooling waterpump 155, a temperature sensor 156, a flow-rate sensor 157, and aflow-rate control valve 158.

The heat accumulation tank 153 is connected to a heat supply line 159,which receives heat transferred via the cooling water line 154, andsupplies the heat to a certain heat demand place or heat demand unit.

In particular, the cooling/heating apparatus according to the secondembodiment of the present invention further comprises a refrigerantheating unit for the hydrogen modifying unit 150. The refrigerantheating unit is adapted to supply the waste heat recovered from thehydrogen modifying unit 150 to the suction-side refrigerant line 167connected to the suction side of the compressor 61 provided in thecooling/heating unit 60 so as to raise the temperature of therefrigerant. In the present embodiment, the modifying unit cooling unit152 serves as the refrigerant heating unit. In this case, therefrigerant line of the cooling/heating unit 60 extends through the heataccumulation tank 153, so that the waste heat of the hydrogen modifyingunit 150 is transferred to the refrigerant line.

Between the suction-side refrigerant lines 67 and 167, connected to thesuction side of the compressor 61, a bypass line 168 and a valve 169 forthe hydrogen modifying unit 150 are provided, so that the refrigerant,having passed through the heat accumulation tank 53 for the fuel cell50, bypasses the heat accumulation tank 153 if necessary.

Also, the cooling/heating apparatus according to the second embodimentof the present embodiment further comprises a control unit 170 designedto control various elements associated with both the fuel cell 50 andthe hydrogen modifying unit 150 based on signals inputted thereto.

Now, operation of the cooling/heating apparatus using the waste heat ofthe fuel cell according to the second embodiment of the presentinvention, having the above-described configuration, will be described.

In general, the operating temperature of the hydrogen modifying unit isapproximately 600 degrees. Thus, the cooling/heating apparatus of thepresent embodiment is able to supply heat to the suction-siderefrigerant line of the compressor during a heating operation in winter,using the waste heat generated from the hydrogen modifying unit, therebyachieving an enhancement in heating performance. Also, thecooling/heating apparatus of the present embodiment is able to supplyheat, generated from both the heat accumulation tanks for the fuel celland the hydrogen modifying unit, to a hot water supplier or otherheating systems.

In this way, as the waste heat generated from the fuel cell 50 and thewaste heat generated from the hydrogen modifying unit 150 are suppliedto the respective refrigerant lines 67 and 167 connected to thecompressor during a heating operation, and the control unit 170 controlsall of valves 58, 59V, and 69 and 158, 159V, and 169 based on avariation in the flow rate of the cooling water and the interiortemperatures of the cooling water lines 54 and 154 and the heataccumulation tanks 53 and 153 sensed by the temperature sensors 56 and156 and the flow rate sensors 57 and 157, it is possible to supply anappropriate amount of heat to the refrigerant line of thecooling/heating unit 60, achieving an enhancement in heatingperformance.

As is apparent from the above description, the cooling/heating apparatususing waste heat of the fuel cell according to the present invention isconfigured so that waste heat generated from the fuel cell or hydrogenmodifying unit is supplied to a refrigerant line of a cooling/heatingunit during the heating operation, thereby achieving an enhancement inheating performance and an enhancement in system efficiency.

Also, in accordance with the present invention, the cooling water can besupplied to the refrigerant line, in a state of being appropriatelyadjusted in the amount and temperature thereof in accordance with a loadvariation of the fuel cell or hydrogen modifying unit. Accordingly, itis possible to supply uniform heat to the refrigerant line, enabling animplementation of the heating operation.

Although the preferred embodiments of the present invention have beendisclosed for illustrative purposes, those skilled in the art willappreciate that various modifications, additions and substitutions arepossible, without departing from the scope and spirit of the inventionas disclosed in the accompanying claims.

1. A cooling/heating apparatus using waste heat of a fuel cellcomprising: the fuel cell; a cooling/heating unit which includes atleast one compressor, a 4-way valve, an outdoor heat exchanger, anexpansion device, and an indoor heat exchanger, to establish a heat pumptype refrigerant cycle; and a refrigerant heating unit to provide thewaste heat recovered from the fuel cell to a refrigerant line of thecooling/heating unit so as to raise the temperature of a refrigerant. 2.The cooling/heating apparatus as set forth in claim 1, wherein therefrigerant heating unit is configured to supply the waste heat to asuction-side refrigerant line connected to the suction side of thecompressor.
 3. The cooling/heating apparatus as set forth in claim 2,wherein the refrigerant heating unit includes: a cooling water line totransfer the heat recovered from the fuel cell; and a heat accumulationtank to transfer the heat, supplied via the cooling water line, to thesuction-side refrigerant line connected to the suction side of thecompressor.
 4. The cooling/heating apparatus as set forth in claim 3,wherein the cooling water line is provided with a temperature sensor anda flow rate sensor to measure the temperature and flow rate of coolingwater, respectively, and is also provided with a cooling water pump tocirculate the cooling water and a flow-rate control valve to adjust theflow rate of the cooling water.
 5. The cooling/heating apparatus as setforth in claim 3, wherein the heat accumulation tank is connected to aline which receives the heat transferred via the cooling water line andsupplies the heat to a heat demand unit.
 6. The cooling/heatingapparatus as set forth in claim 3, wherein the suction-side refrigerantline, connected to the suction side of the compressor, is provided witha bypass line and a valve unit to cause the refrigerant to bypass theheat accumulation tank.
 7. The cooling/heating apparatus as set forth inclaim 1, further comprising: a hydrogen modifying unit to supplyhydrogen to the fuel cell; and a refrigerant heating unit for thehydrogen modifying unit which supplies waste heat recovered from thehydrogen modifying unit to a suction-side refrigerant line connected tothe suction side of the compressor included in the cooling/heating unit.8. The cooling/heating apparatus as set forth in claim 7, wherein therefrigerant heating unit for the hydrogen modifying unit includes: acooling water line to transfer the heat recovered from the hydrogenmodifying unit; and a heat accumulation tank to transfer the heat,supplied via the cooling water line, to the suction-side refrigerantline connected to the suction side of the compressor.
 9. Thecooling/heating apparatus as set forth in claim 8, wherein the coolingwater line is provided with a temperature sensor and a flow rate sensorto measure the temperature and flow rate of cooling water, respectively,and is also provided with a cooling water pump to circulate the coolingwater and a flow-rate control valve to adjust the flow rate of thecooling water.
 10. The cooling/heating apparatus as set forth in claim8, wherein the heat accumulation tank for the hydrogen modifying unit isconnected to a line which receives the heat transferred via the coolingwater line and supplies the heat to a heat demand unit.
 11. Thecooling/heating apparatus as set forth in claim 8, wherein thesuction-side refrigerant line, connected to the suction side of thecompressor, is provided with a bypass line and a valve to cause therefrigerant to bypass the heat accumulation tank.
 12. A cooling/heatingapparatus using waste heat of a fuel cell comprising: the fuel cell; ahydrogen modifying unit to supply hydrogen to the fuel cell; acooling/heating unit which includes at least one compressor, a 4-wayvalve, an outdoor heat exchanger, an expansion device, and an indoorheat exchanger, to establish a heat pump type refrigerant cycle; and apair of first and second refrigerant heating units to provide the wasteheat recovered from both the fuel cell and the hydrogen modifying unitto respective refrigerant lines of the cooling/heating unit so as toraise the temperature of a refrigerant.
 13. The cooling/heatingapparatus as set forth in claim 12, wherein the refrigerant heatingunits are configured to supply the waste heat to suction-siderefrigerant lines connected to the suction side of the compressor. 14.The cooling/heating apparatus as set forth in claim 13, wherein thefirst refrigerant heating unit includes: a cooling water line totransfer the heat recovered from the fuel cell; and a heat accumulationtank to transfer the heat, supplied via the cooling water line, to thesuction-side refrigerant lines connected to the suction side of thecompressor.
 15. The cooling/heating apparatus as set forth in claim 14,wherein the cooling water line is provided with a temperature sensor anda flow rate sensor to measure the temperature and flow rate of coolingwater, respectively, and is also provided with a cooling water pump tocirculate the cooling water and a flow-rate control valve to adjust theflow rate of the cooling water.
 16. The cooling/heating apparatus as setforth in claim 14, wherein the heat accumulation tank is connected to aline which receives the heat transferred via the cooling water line andsupplies the heat to a heat demand unit.
 17. The cooling/heatingapparatus as set forth in claim 14, wherein the suction-side refrigerantline, connected to the suction side of the compressor, is provided witha bypass line and a valve unit to cause the refrigerant to bypass theheat accumulation tank.
 18. The cooling/heating apparatus as set forthin claim 12, wherein the second refrigerant heating unit is adapted tosupply waste heat recovered from the hydrogen modifying unit to anassociated one of the suction-side refrigerant lines connected to thesuction side of the compressor included in the cooling/heating unit. 19.The cooling/heating apparatus as set forth in claim 18, wherein thesecond refrigerant heating unit for the hydrogen modifying unitincludes: a cooling water line to transfer the heat recovered from thehydrogen modifying unit; and a heat accumulation tank to transfer theheat, supplied via the cooling water line, to the suction-siderefrigerant line connected to the suction side of the compressor. 20.The cooling/heating apparatus as set forth in claim 19, wherein thesuction-side refrigerant line, connected to the suction side of thecompressor, is provided with a bypass line and a valve to cause therefrigerant to bypass the heat accumulation tank.